1. Field of the Invention
The present invention relates to a miniature circuit breaker, in which an elastic contact piece connects two terminals of a circuit, thereby electrically connecting the circuit. One end of the elastic contact piece is fixed and bended to form an elastic curved section. The elastic curved section reduces the length of the elastic contact piece, thereby effectively reducing the size of the elastic contact piece. Thus, the objective to miniaturize the circuit breaker is achieved.
2. The Prior Arts
Generally, in a large-scale electric circuit loops, individual circuit loop uses fuses, circuit breakers or thermal circuit breakers to protect the circuit from overload or overheat that cause a fire, thereby providing a level of safety against overload conditions.
Some electronic or electrical appliances, such as high-end electronics, data processors, power consuming heaters, etc, include thermal circuit breakers at power cords or inside the appliances as circuit protection. The thermal circuit breakers interrupt the electric current when the current is excessive or the circuit is overheated. Thus the thermal circuit breakers prevent the electronic or electrical appliances from being burned up when the current of the electronic and electrical appliances is over-loaded. In the same time, the thermal circuit breakers prevent the overload conditions of a single electronic or electrical appliance from causing overload of the individual circuit loop or the whole circuit loops, which results in failures of other appliances in the individual circuit loop or the whole circuit loops.
The conventional thermal circuit breakers in single electronic appliance as described above uses an elastic contact piece to connect with two terminals for connecting the circuit loop. The elastic contact piece of the conventional thermal circuit breaker deforms and flips backward to cut off the circuit loop as the circuit is overheated. The conventional thermal circuit breaker can automatically break off the circuit when the wire is over heated. However, it has many disadvantages as follows.
First of all, the concave or convex elastic contact piece of the conventional thermal circuit breaker would deform, and respectively flip into convex or concave shape after heated. No matter the elastic contact pieces are punched or assembled to form the curved shape, it is hard to keep every elastic contact piece with the same thickness, curvature and structural characteristics. Therefore, it is difficult to precisely control the responsive temperature to break off the circuit. That is, the responsive temperature has great error, and quality control in manufacturing the elastic contact pieces is a difficult task.
Secondly, the curved elastic contact piece of the conventional thermal circuit breaker is not sensitive to the responsive temperature to deform and flip after heated, so it can not protect the electrical appliances from overload or overheat in time.
Thirdly, because length and size of the elastic contact pieces can not be reduced, the size of the conventional thermal circuit breakers is rather big and incapable of being miniaturized. The large circuit breakers not only increase the sizes of the electrical appliances, but also ruin the aesthetics of the appliances.
The amount of material and the manufacturing cost for the thermal circuit breakers can not be reduced.